Intermittent web-pulling mechanism



Jan. 25, 1966 R. o. GIBB ETAL 3,230,597

INTERMITTENT WEB-PULLING MECHANISM Filed March 1, 1963 3 Sheets-Sheet 1 FIG. 2

ELECT SUPPUY l!- NR VENT SUPPtY INVENTORS ROBERT o. GIBB Y JOHN H. HANNAWAY M,M&m

ATTORNEYS Jan. 25, 1966 R. o. GIBB ETAL 3,230,597

INTERMITTENT WEB-PULLING MECHANISM Filed March 1, 1965 5 heetsh e 2 FIG. 4 42 1N VENTORS ROBERT 0. GIBB BY JOHN H. HANNAWAY M,M&W

ATTORNEYS Jan. 25, 1966 R. o. GIBB ETAL INTERMITTENT WEB-PULLING MECHANISM 3 Sheets-Sheet 3 Filed March 1, 1963 INVENTORS ROBERT O. GIBB lllllllll.

BY JOHN H. HANNAWAY ATTORNEYS itioned patent. .rolls soarranged tend to damage many Web materials United. States Patent INTERMITTENT WEE-TULHNG MECHANESM Robert 0. Gibb, Rockland Mass and John H. Hannaway,

Pawtucket, R.l., assignors to Mount Hope Machine Company, incorporated, T aunton, Mass, a corporation of -Massachusetts Filed Mar. 1, 1963,Ser. No. 261,955 5 Claims. (Cl. 26-514) termittently stretching portions of the web transversely or weft-wise, which induces an incidental distortion of the warp or longitudinal elements. The characteristics of the warp distortions are detected at longitudinallyspaced points to produce differential signals, which accurately indicate the condition of the weft elements.

The intermittent web-pulling means disclosed by the patent, generally comprise two or more nip-roll units, each of which includes a pair of rolls arranged to grip opposite surfaces of the Web. One of the rolls of each pair is movableinto and out of engagement with the web, for intermittent pulling action. The planes of rotation of the nip-rolls are turned at an angle to the longitudinal direction of web travel, so as to introduce a lateral reaction component for stretching the web weft-wise.

The angular relation of the nip-rolls to the direction of travel of the web is fixed during operation of the apparatus, according to the disclosure of the aforemen- It has been found in practice that nipsli ghtly, marring or bruising the surfaces. This may be caused by local disorientation of the warp or weft threads with respect to the planes of rotation of the rolls, as the web is intermittently gripped. Furthermore, there appears to be some slippage of cloth through the niprolls, which results in reduction in the strength of the detection signals.

It is the primary object of our invention to provide an improved intermittent web-pulling mechanism which substantially reduces the marring of a traveling web.

This mechanism may also afiord increased detection signal strengthin a weft-detecting apparatus as disclosed by the aforementioned patent. Further objects and advantages of the invention will appear as the following description. proceeds.

.Briefly stated, according to a preferred embodiment thereof, our improved intermittent web-pulling mechanism includes a plurality of nip-roll units, each comprising a pair of nip-rolls whose axles are supported in a carrier. [I he carrier is supported in a base for rotation about an axis normal to the plane of a traveling web; the nip-roll axles are thus angularly movable so that the angular relation between the planes of rotation of the rolls and the direction of travel of the web may be varied. We

-further.provide means for oscillating the carrier and the supportednip-rolls between a position in which the rolls are parallel to the direction of travel of the web, and a position in which the rolls are angularly offset. The extent of .web pulling action is dependent upon this angular relationship: in the parallel position, no transverse pulling action takes place, While, in the angularly-offset position the web is stretched transversely. We have found that by intermittently oscillating the nip-rolls in this "ice manner, an intermittent web-pulling action may be secured with reduced marring or bruising of the cloth. Furthermore, slippage through the nip of the rolls is reduced; the detection signal strength may be correspondingly improved in practice.

While the rolls may be maintained in contact with the web when in the parallel non-stretching position, that is, during the interruptions in detector operation, We prefer to follow the practice of the aforementioned patent in this respect, by mounting at least one roll of each unit reciprocably in its carrier for movement in and out of engagement with the web. The nip-rolls are preferably closed on the web before being turned from the parallel position to the angularly-offset position; similarly, they should return to the parallel position before being opened.

In a preferred embodiment, we provide a common control system for simultaneously energizing motive means for oscillating thecarrier of each nip-rollunit, and motive means for reciprocating one of the rolls of each pair. To conform to the foregoing sequence of operation, the motive means have unequal actuation times following simultaneous energization. In one form, we provide a double-acting fluid motor for oscillating the carrier, and a single-acting fluid motor with a relatively slow-acting spring return for reciprocating a nip-roll in the carrier. Engagement of the rolls requires a relatively short stroke, and so occurs before the carrier has turned substantially from the parallel position. The positive return of the double-acting motor causes the carrier to return-from the offset to the parallel position, before the spring return of the single-acting motor has substantially opened the niprolls.

While the specification concludes with claims particularly pointing out the subject matter which we regard as our invention, it is believed that a clearer-understanding maybe gained from the following detailed description of a preferred embodiment, referringto the accompanying drawings, in which:

FIG. 1 is a schematic plan view of a weft-detection apparatus incorporating our improved web-pulling mechanism, showing-the nip-roll units in a parallel or inactive position;

FIG. 2 is a view similar to FIG. 1, but showing the nip-roll units turned to an angularly-oifset position for transversely stretching the web;

FIG. 3 is a schematic view in elevation of the apparatus, showing a preferred control system;

FIG. 4 is a view in side elevation of one of the nip-roll units;

FIG. 5 is a sectional plan view of the nip-roll unit taken along line 55 in FIG. 6, looking in the direction of the arrows; and

FIG. 6 is a fragmentary view-in front elevation of the nip-roll unit.

Referring to FIGS. 1-3, the improved intermittent web-pulling means includes at least two nip-rolls units 1, which are arranged in transversely-spaced relation to a web ltl traveling longitudinally in a direction indicated by the arrow. In its passage through the detection apparatus, the web is supported for travel substantially in a plane by guide rolls (not shown), as more fully described in the aforementioned US. Patent No. 2,795,- 029. One or more pairs of detectors l2 and 13 are provided; each pair is arranged in tandem, i.e., in'spaced relation longitudinally of the web, to provide a differential detection signal when the web is stretched transversely by the nip-roll units. The detectors shown have caster wheels 14 and 15, the difference in whose angular displacements is reflected by the detection signal, but the specific nature of the detectors is not critical. The

detection apparatus may utilize any means capable of detecting the characteristics of distortion of the warp elements induced by transverse stretching of the web.

Each of the nip-roll units includes a pair of rolls 16 and 17, which are rotatably supported for engagement with the opposite surfaces of the web by means of a carrier unit generally designated 18. The carrier is supported in a base (not shown in FIGS. 1 and 2) for oscillation about an axis normal to the plane of the web, for movement of the nip-rolls between a position parallel to the direction of web travel, as shown in FIG. 1, and a position angularly offset from the direction of travel, as shown in FIG. 2. In the parallel position, the rolls produce no transverse stretching effect, since the resultant of their reaction to rotation by the web is parallel to the direction of web travel. In the singularly-offset position, however, reaction components are produced longitudinally and transversely of the web, and a stretching action takes place as represented in FIG. 2.

Each carrier 13 includes a housing portion for reciprocably supporting the axle of the roll 16, a yoke portion 22 which arches outwardly to permit the web to pass between the rolls, and a rotary bearing element or turntable 24 in which the axle of the lower roll 17 is rotatably mounted. Means for oscillating the carriers 18 between the alternate positions comprise a pair of double-acting fluid motors 26, each having a piston rod 28 pivotally connected at 32 with an arm portion of a carrier. An adjustable stop 34 is mounted on a portion of the piston rod protruding from the opposite end of each motor 26, by means of which the terminal angle of the offset nip-roll position may be adjusted.

It is preferred to disengage the nip rolls from the web during intervals when they are in the parallel position, and for this purpose the upper rolls 16 have their axles 70 drivingly connected (preferably by means of overtravel spring mechanisms, not shown in FIGURES 13) with piston rods 38 of single-acting fluid motors 40 having return springs 106. The motors 26 and 46 are energized from a common fluid pressure source, by means of a branched inlet conduit 42 connected to the motors 4t) and the motors 26, and a branched conduit 44 connected to the opposite ends of the motors 26. Connection of an air supply conduit and a vent conduit are alternatively established with the conduits 42 and 44 by means of a conventional four-way valve, which has alternate positions for pressurizing one of the conduits and venting the other. Control of the valve for cyclical operation, is achieved by suitable timing means, illustrated as an electrical timer intermittently energizing a solenoid.

In the position shown in FIGURE 3, the conduit 44 is pressurized and the motors 26 have turned the nip rolls to the parallel position. Upon reversal of the valve position by the timer, both the motors 26 and the motors 40 are energized by means of the conduit 42, in directions to turn the rolls to the angularly-oifset position, and also to close the nip-rolls on the web. However, the motors 26 have a relatively longer stroke than that required to close the nip-rolls, and consequently the rolls close before they have been turned substantially from the parallel position. The timer subsequently reverses the four-way valve to vent the conduit 42 and pressurize the conduit 44, thus positively driving the carriers 18 angularly towards the parallel position. This positive actuation transpires more rapidly than the separation of the nip-rolls by the springs 100, which are delayed by the weight of the motors 49 and the rolls 16, and the exhausting of motors 40. Therefore, the rolls return to the parallel position before they are disengaged substantally from the web.

Referring to FIGS. 4-6, a nip-roll unit is shown in detail on an enlarged scale. .The carrier unit 18 includes the housing portion 20, which is secured upon the yoke portion 22 by suitable fastening means such as machine yoke; and the turntable 24 fastened to the yoke by means of a machine screw 52. The entire carrier is rotatably mounted by means of the turntable 24 in a circular bearing opening 54 of a base member 56. The turntable is formed with a circumferential lip 58 which rests upon the base and with a groove 60 into which a plurality of retaining screws 62 protrude, to secure the turntable rotatably on the base. The lower nip-roll 17 is rotatably mounted on an axle-forming screw 64 in a terminal port'on 66 of the yoke 22. The nip-roll 17 extends upwardly through a slot 68 in the turntable 24, for engagement with the lower surface of the web,

The roll 16 is rotatably mounted upon an axle-forming screw 76, which is supported for vertical reciprocation in the housing portion 20 by means of a tubular slide 72. This reciprocal movement is guided by means of a slide bearing 74 received on the axle and slidably engaged in a guide recess 76 formed in the housing 20. The tubular slide 72 is slidably mounted in the housing by means of slide bearings 78 receivedin bushings Sil'and 82. The bushing it is secured in the housing by a collar 84 and a snap ring 86, while the bushing 82 is secured by a disc 89 and a snap ring 87.

The slide 72 is drivingly connected with the piston rod 33 of the single acting fluid motor 40. For delayed return of the roll 16 from the nipped to the raised position, a compression spring 1% is engaged between the slide 72 and the disc 89. As the motor 40 is vented, the return spring tends to drive the slide 72 upwardly, but the inertia of the reciprocable parts 16, 40, and 72 and the delayed exhaust of the motor 40 delays separation of the nip-rolls, preferably until the carrier 18 is returned to the parallel position by the motor 26.

The arm portion 3%] of the carrier 13 is connected with the piston rod 28 of the motor 26 by means of a pivotforming screw 32, the piston rod being positioned thereon by means of a bushing 108. The motor 26 is pivotally mounted in a bifurcated support bracket 110, which is secured to the lower surface of the base 56 by means of screws 112. The pivotal connection is made by pivot pins 114, extending into a bushing 116 into which is threaded a fitting 118 secured to an end of the motor. The motor 26 is thus arranged for oscillation of the carrier and the nip-rolls between positions shown in FIG. 5.

Each nip-roll unit is mounted adjacent to an edge of the web by means of the base 56; in the preferred embodiment, the base is mounted on a screw 124. and a rod or shaft 126, which extend in parallel relation transversely of the web to support both nip-roll units for simultaneous adjustment. This arrangement may be as described in the aforementioned U.S. Patent No. 2,795,029, and no further detailed description is believed necessary." Thebase 56 is secured by machine screws 128 in a mounting plate 138, which is in turn secured by machine screws 132 in'a mounting block 134. The screw 124 is threadedly engaged in the mounting block for transverse adjustment thereof, and the support rod 126. is slideably received through the mounting block to support the nip-roll units in adjusted positions. V

As best shown in FIGURE 6, each of the nip-rolls 16 and 17 is formed with a circumferential flange 136 in which is received an annular rubber ring ortire 138, to

engage the web resiliently. The wheel assembly is com-' pleted by a retaining disc 14% secured by screws142. The nip-rolls are mounted for rotation on their axles by dual bearing units 144.

While we have illustrated and described a preferred embodiment of our improved intermittent web-pulling mechanism by way of illustration, it will be apparent to those skilled in theart that various changes and modifications may be made without departing from the true spirit and scope of the invention, which we therefore intend to define in the appended claims without limitation to the details of the foregoing embodiment.

What we claim is:

1. An intermittent web-pulling mechanism for transversely stretching a longitudinally-traveling planar web, comprising a plurality of nip-roll units mounted for engaging the web at transversely-spaced portions thereof, each of said nip-roll units comprising a pair of nip-rolls, a carrier, a pair of axles rotatably mounting said niprolls in said carrier in spaced relation to opposite surfaces of the web, at least one of said axles being mounted in said carrier for reciprocation with a component of direction normal to the plane of the Web, means for reciprocating said one axle for intermittent gripping engagement of said nip-rolls with the surfaces of the web, a base, said carrier being mounted in said base for rotation about an axis normal to the plane of the web, means for oscillating said carrier about said normal axis to move said nip-rolls between positions in which the planes of rotation thereof are substantially parallel to, and are offset at an angle from, the direction of travel of the web, and common control means for selectively energizing said reciprocating means and said oscillating means simultaneously to engage said nip-rolls with the web and to turn said rolls from said parallel position to said offset position, and for selectively energizing said reciprocating means and said oscillating means simultaneously to drive said nip-rolls out of gripping engagement with the web and toward said parallel position.

2. An intermittent web-pulling mechanism as recited in claim 1, in which a slide reciprocably mounts said one of said axles in said carrier, and said reciprocating means includes selectively-actuatable motive means drivingly connected with said slide for engaging said nip-rolls and a compression spring biasing said slide in a direction for returning said nip-rolls to a disengaged position upon deactuation of said motive means.

3. An intermittent web-pulling mechanism as recited in claim 1, in which said reciprocating means and said oscillating means are constructed and arranged to engage said nip-rolls with the web prior to substantial movement of said nip-rolls toward the offset position, and to return said nip-rolls to the parallel position prior to substantial disengaging movement of said nip-rolls.

4. An intermittent web-pulling mechanism as recited in claim 1, in which said carrier comprises a housing reciprocably supporting said one of said axles, a turntable rotatably mounted in said base and supporting the other of said axles, and a generally U-shaped yoke connecting said turntable with said housing and admitting the traveling web between said nip-rolls.

5. An intermittent web-pulling mechanism for transversely stretching a longitudinally-traveling planar web, comprising a plurality of nipoll units mounted for engaging the web at transversely-spaced portions thereof, each of said nip-roll units comprising a pair of nip-rolls, a carrier, a pair of axles rotatably mounting said nip-rolls in said carrier in spaced relation to opposite surfaces of the Web, a base, said carrier being mounted in said base for rotation about an axis normal to the plane of the web, means for oscillating said carrier about said normal axis to move said nip-rolls between positions in which the planes of rotation thereof are substantially parallel to, and are offset at an angle from, the direction of travel of the web, and automatic control means constructed and arranged for intermittently energizing said oscillating means at predetermined intervals to turn said rolls from said parallel position to said offset position, and then energizing said oscillating means to return said nip-rolls toward said parallel position.

References Cited by the Examiner UNITED STATES PATENTS 1,203,719 11/ 1916 Edmunds 26-65 X 1,645,036 10/ 1927 Bacon 26-67 X 1,739,993 12/1929 Tandel 2667 2,316,798 4/1943 Luebbe 226181 X 2,417,447 3/ 1947 Robertson 2667 2,795,029 6/ 1957 Robertson et al 2651.4 3,147,898 9/1964 Huck 2665 X DONALD W. PARKER, Primary Examiner. 

5. AN INTERMITTENT WEB-PULLING MECHANISM FOR TRANSVERSELY STRETCHING A LONGITUDINALLY-TRAVELING PLANAR WEB, COMPRISING A PLURALITY OF NIP-ROLL UNITS MOUNTED FOR ENGAGING THE WEB AT TRANSVERSELY-SPACED PORTIONS THEREOF, EACH OF SAID NIP-ROLL UNITS COMPRISING A PAIR OF NIP-ROLLS, A CARRIER, A PAIR OF AXLES ROTATABLY MOUNTING SAID NIP-ROLLS IN SAID CARRIER IN SPACED RELATION TO OPPOSITE SURFACES OF THE WEB, A BASE, SAID CARRIER BEING MOUNTED IN SAID BASE FOR ROTATION ABOUT AN AXIS NORMAL TO THE PLANE OF THE WEB, MEANS FOR OSCILLATING SAID CARRIER ABOUT SAID NORMAL AXIS TO MOVE SAID NIP-ROLLS BETWEEN POSITIONS IN WHICH THE PLANES OF ROTATION THEREOF ARE SUBSTANTIALLY PARALLEL TO, AND ARE OFFSET AT AN ANGLE FROM, THE DIRECTION OF TRAVEL OF THE WEB, AND AUTOMATIC CONTROL MEANS CONSTRUCTED AND ARRANGED FOR INTERMITTENTLY ENERGIZING SAID OSCILLATING MEANS AT PREDETERMINED INTERVALS TO TURN SAID ROLLS FROM SAID PARALLEL POSITION TO SAID OFFSET POSITION, AND THEN ENERGIZING SAID OSCILLATING MEANS TO RETURN SAID NIP-ROLLS TOWARD SAID PARALLEL POSITION. 